Preparation of iodine pentafluoride



Feb. 6, 1968 H. G. TEPP 3,367,745

' PREPARATION OF IODINE PENTAFLUORIDE Filed Feb. 8, 1966 2 Sheets-Sheet1 INVENTOR HANS G.TEPP

ATTORNEY Feb. 6, 1968 H. G TEPP 3,367,745

PREPARATION OF IODINE PENTAFLUORIDE Filed Feb. 8, 1966 2 Sheets -SheetI? INVENTOR HANS G.TEPP

ATILORNEY United States Patent 5 Claims. (Cl. 232ll5) ABSTRACT OF THEDISCLOSURE This application relates to a process for the manufacture ofiodine pentafluoride from elemental iodine and fluorine by fluorinatingiodine dissolved in an inert solvent medium, preferably iodinepentafluoride. In a first embodiment of the process the quantities ofthe reactants are controlled by the use of valves connected tophotoelectric cells through which the reactants and product of theprocess are flowed. In a second embodiment of the process of thisinvention the need for close feed control of the iodine and fluorinereactants is rendered unnecessary by the use of two reaction zones andtwo holding zones interconnected for flow in such a manner as to insurethe complete utilization of all iodine and fluorine introduced into thereaction zones.

This invention relates to iodine pentafluoride and more particularly toa new and improved method for the manufacture of iodine pentafluoride.

This application is a continuation in part of my application Serial No.380,797 filed July 7, 1964, and now abandoned.

Iodine pentafluoride, a known compound, is a colorless liquid whichfreezes at 9.6- C. and boils at 98 C. and has a specific gravity of 3.15at 25 C. It may be prepared by passing fluorine gas over a bed ofinitially solid iodine crystals. The reaction is rapid and exothermicbut ineflicient as to low fluorine utilization. Despite full watercooling of the reactor tube, the heat of reaction melts and vaporizesiodine in excess of that utilized which tends to contaminate the iodinepentafluoride product with excess iodine. To prevent this, an excess offluorine is fed to fluorinate all such vaporized iodine with the resultthat not only is the fluorine utilization low, but also some undesirable1P is made; a yield loss of both fluorine and iodine.

An object of the present invention is to produce iodine pentafluoride ina simple, eiiicient and continuous manner. Another object is to produceiodine pentafluoride in high yield with a high degree of purity. Otherobjects and ad vantages will be apparent from the following detaileddescription.

In accordance with the present invention, there is provided a processfor the production of iodine pentafluoride which comprises passingelemental fluorine in contact with a solution of dissolved iodine in aninert solvent medium to convert the elemental fluorine and iodine intoiodine pentafluoride.

FIGURE 1 of the accompanying drawings diagrammatically illustrates amethod of practicing the process of this invention.

FIGURE 2 of the accompanying drawings diagrammatically illustrates thepreferred method of practicing the process of this invention.

Generally, practice of the invention includes subjecting iodinedissolved in a liquid inert medium to the action of gaseous fluorine atsubstantially atmospheric pressure and at a temperature within the rangeof 10 to 98 C. preferably to 60 C. in quantity and for a time 3,367,745Patented Feb. 6, 1968 ICC sufficient to fiuorinate the iodine in theinert solvent to form the desired iodine pentafluoride product and recvering the latter from the resulting reaction products. Moreparticularly, gaseous fluorine is continuously metered and fed into asuitable reactor where it is passed countercurrent and in contact withabout 0.1 to 5.0% preferably 0.4 to 1.0% by weight iodine dissolved inan inert solvent medium to form iodine pentafluoride.

The reaction involved in practice of the invention may be represented byinert medium 5F2 I2 The solvent employed according to the process of theinvention may be any solvent which is inert to the reactants, thereaction products, and the equipment utilized. In addition, the solventsshould be capable of dissolving iodine in an amount of up to about 5.0%by weight. Examples of suitable solvents include SbF and iodinepentafluoride. BRF although not inert, can also be used as a solvent.

Iodine pentafluoride is the preferred solvent. The iodine reactant maybe dissolved in the iodine pentafluoride by any suitable procedure knownin the art. For example, the iodine pentafluoride may be circulatedthrough iodineladen leach vessels wherein the circulated iodinepentafluoride liquid would pick up and dissolve the iodine in an amountof up to about 5.0% by weight of iodine. Alternatively, the iodine maybe fed into a circulating solvent via vaporization thus replacing theleach vessels.

With regard to mole ratio of fluorine to iodine, theoreticalrequirements are approximately five moles of fluorine to one of iodine.Larger amounts of fluorine that is, more than five moles of fluorine permole of iodine may be employed, however, larger amounts of an excess ofsix moles of fluorine tend to pass unreacted through the reactor thuscausing a loss of valuable fluorine gas. An amount of less than 5 molesof fluorine per mole of iodine does not give as satisfactory results dueto iodine contamination of product. For best results, it is preferred toemploy 5 to 5.5 moles of fluorine per mole of iodine. The temperature atwhich the reaction takes place is within the range of 10* to 98 C.preferably 20 to C. Temperatures substantially in excess of thesetemperatures tend to increase the formation of by-prodnets and are,therefore, not desirable.

Although the process can be operated at sub-atmospheric andsuperatrnospheric pressure, an important advantage of the operation isthat the process can be conducted at substantially atmospheric pressureto about 15 p.s.i.g. The reaction between fluorine and iodine is almostinstantaneous. However, the contact time may be varied considerablywithout noticeable disadvantage. Generally, increasing contact time andreaction temperature results in higher reactivity. Significantconversions are effected at contact times as short as 3 seconds andcontact time may be as high as 60 seconds.

The operation of the process may be conducted either batch-wise or in acontinuous manner. In a preferred procedure, a body of iodinepentafluoride is contained in a tank, equipped with provision forcontinuously drawing off a portion of iodine pentafluoride which iscirculated through iodine leach vessels for iodine pickup. Theiodineladen iodine pentafluoride is then passed through a re actor incountercurrent contact with fluorine gas and iodine pentafluoride isdischarged from the reactor into the tank where a portion substantiallyequal in weight to the iodine pentafluoride made in the reactor iscontinuously drawn off as product.

Referring more particularly to FIGURE 1, an iodine solution of iodinepentafluoride containing about 0.1 to 1 /2% iodine by weight isintroduced through line 1 into the top of reaction vessel 3 incountercurrent contact with fluorine gas entering the bottom of thereaction vessel through line 2. The reaction vessel employed isdesirably of the type which contains an inert packing material such asnickel helices or raschig rings to disperse the liquid iodinepentafluoride so that better contact between the fluorine gas and iodineis effected. The column is fabricated from a material which is inert orsubstantially inert to the reactants and the reaction products. Suitablematerials include monel, stainless steel, mild steel, Inconel andHastelloy C. In order to maintain the temperatures within the desiredrange for the reaction, the reaction vessel is equipped with provisionfor cooling such as a cooling jacket surrounding the reaction vesselthrough which a cooling medium such as water flows.

Under the technique of operation, the iodine pentafluoride flows downthe reaction vessel 3 countercurrent and in contact with the upflowingfluorine gas causing a reaction between the fluorine gas and the iodinecontained in the iodine pentafluoride. By this procedure, the exothermiceffect of the reaction is minmized because the heat produced by thereaction is dissipated in the iodine pentafluoride solvent and togetherwith the cooling means of the reaction vessel, the temperature may beeasily maintained within the desired range of about 20 to 60 C. Thepressure within the reaction vessel is substantially atmosphericpressure, although higher or lower pressures may be employed if desired.Normally by the reaction of iodine and fluorine there is produced inaddition to the desired iodine pentafluoride product quantities ofiodine heptafluoride, particularly at higher temperatures. As a resultof the employment of iodine pentafluoride as a solvent for the iodinereactants, however, the formation of iodine heptafluoride is minimized.Vapors of iodine hepta fluoride formed in the reaction together with anyunreacted fluorine gas resulting from process upsets destroying theratio of fluorine to iodine in the feeds are discharged from reactionvessel 3 through line 4 and into vessel 5. Generally, iodineheptafluoride and fluorine react with iodine to produce iodinepentafluoride. Thus, by passing the gaseous iodine heptafluoride andfluorine from the reaction vessel 3 in contact with iodine crystalscontained in cleanup vessel 5, the iodine heptafluoride and fluorine isconverted to iodine pentafluoride adding to the yield of the desiredproduct. The cleanup vessel is preferably constructed of an inertmaterial such as monel and is equipped with provision for containingiodine crystals. For this purpose, there may be employed a basketconstructed of a monel screen which is suspended in the vessel to permitthe impurities to pass through in contact with the iodine contained inthe basket. The iodine pentafluoride which is formed by passing theimpurities in contact with the iodine is discharged from cleanup vessel5 through line 6 and is introduced into product tank 7. Anynoncondensable wastes which have not been converted to iodinepentafluoride leave cleanup vessel 5 through line 8.

The iodine pentafluoride formed in the reactor 3 is discharged throughline 9 and flows through a photometer 10. The photometer employed may beof the conventional type having a sight glass and means for emitting alight beam on one side which contacts a photosensitive cell on theopposite side. The photosensitive cell senses the amount of lighttransmission which passes through the sight glass. The degree or amountof light transmission is directly related to the quantity of free iodinein the iodine pentafluoride solution. The iodine pentafluoride isnormally a clear and water-white liquid. Thus, the photometer can beused to control the feed of fluorine based on the discoloration of clearwater-white iodine pentafluoride by excess iodine, varying in degrees ofdeep red to colorless in going from 1% iodine in excess to none. Ifthere is an excess of iodine in the products as determined by the colorof the product, the flow of fluorine gas is increased or theconcentration of iodine entering through line 1 is reduced. The productiodine pentafluoride leaving the photometer :10 enters product tank 7where the iodine pentafluoride is maintained at a fixed level by meansof an overflow pipe 11 through which the iodine pentafluoride iscontinually being discharged during operation of the process. The iodinepentafluoride produced according to the process is in a high degree ofpurity. However, if further purification is desired, the product may hedirected to a suitable distillatio-n apparatus, not shown, to removepossible hydrogen fluoride, iodine, or fluorine contamination. A portionof the iodine pentafluoride in the product tank containing little or nodissolved iodine is continuously withdrawn from product tank 7 throughline 12 by means of pump 13 where it is directed through line 14 foriodine pickup for use in the process. In continuous operation, there maybe provided a plurality of leach vessels 15 and 16 containing iodinecrystals and the iodine pentafluoride solution is continuouslyintroduced into the leach vessels 15 and 16 entering through lines 17and 18 respectively in contact with the iodine crystals until thedesired Weight of iodine in solution is reached. The technique ofoperation is such that when one of the leach vessels is not inoperation, the flow of the iodine pentafluoride may be stopped by meansof valves 1.9 or 21. The iodine pentafluoride containing the dissolvediodine leaves the leach vessels 15 and 16 through lines I? and 21respectively and enter line 1 Where they are passed through anotherphotometer 22, where the color of the iodine pentafluoride liquid ischecked. Iodine pentafluoride liquid may bypass leach tanks 15 and 16through line 20 Where it is desired to lower the iodine concentration inthe iodine pentafluoride solution. The flow of iodine pentafluorideliquid through line 20 may be controlled by means of valve 23. Theiodine pentafluoride liquid leaving the photometer 22 continues its pathalong line 1 and is introduced into the top of reaction vessel 3.

In another and more preferred technique, elemental fluorine iscontinuously passed in contact with iodine pentafluoride containingdissolved iodine in a first reaction zone to effect reaction of theelemental fluorine and iodine to produce iodine pentafluoride. Theiodine pentafluoride is continuously discharged from the first reactionzone and directed back to a first holding zone containing a body ofiodine pentafluoride and a source of iodine, while any unreactedfluorine is passed to a second reaction zone as explained hereinafter.

A portion of the iodine pentafluoride in the first holding zone isdirected back to the first reaction zone for contact with fluorine gasand another portion of iodine pentafluoride in the first holding zone iswithdrawn and directed to a second holding zone containing a body ofiodine pentafluoride having small amounts of iodine dissolved therein.The iodine pentafluoride in the second holding zone containing smallamounts of iodine is continuously discharged and directed to a secondreaction zone where it is passed countercurrent with unreacted fluorinegas from the first reaction zone to eifect reaction of fluorine andiodine to produce iodine pentafluoride. Iodine pentafluoride isdischarged from the second reaction zone and a portion directed back tothe second holding Zone while the remaining portion is directed to adistillation procedure, not shown, for further purification if desired.Any unreacted fluorine gas discharged from the second reaction zone maybe recirculated back to the first reaction zone.

By employing this process scheme, no feed control of the iodine andfluorine reactants is necessary. The iodine content of the iodinepentafluoride is always maintained at the level of saturation for theoperating temperature in the first holding zone by having a source ofiodine such as iodine crystals in excess contained in the first holdingzone. The iodine-laden iodine pentafluoride in the first holding zone isthen circulated at full rate in contact with fluorine gas in the firstreaction Zone wherein the fluorine gas at any practical rate passes intothe first reaction zone in contact with the dissolved iodine of theliquor. Any unreacted fluorine or iodine pentafluoride vapor passing outof the first reaction zone continues into a second reactionzone whereeither component is absorbed or reacted by the circulating liquor fromthe second holding zone. The make of iodine pentafluoride accumulates inthe first holding zone until it overflows to the second holding zonecarrying with it some iodine in solution thus, automatically providingsome iodine for reaction in the second reaction zone. In this manner, nocontrol over iodine concentration is necessary for its constant excessin the mass of iodine pentafluoride circulated through the firstreaction zone is always ample to react with the virgin fluorine feed.Another advantage of this operation is that the system can be operatedat temperatures from about C. up to the actual boiling point of theiodine pentafluoride (calculated at about 98 C. at a latm. pressure),although temperatures within the range of to 60 C. are preferred. Thehigher the temperatures employed in the reaction, the greater thesolubiiity of the iodine in the iodine pentafluoride and depending onthe temperatures for the reaction, there may be dissolved in the iodinepentafluoride liquid an amount of iodine within the range of 0.1 up toabout 5% by weight iodine dissolved in the iodine pentafluoride.

Referring to FIGURE 2, there is illustrated a two-stage reaction processcomprising a first stage including a first reaction zone and a firstholding zone 26. Iodine pentafluoride containing dissolved iodine isintroduced through line 24 into the top of first reaction zone 25 incountercurrent contact with fluorine gas entering the lower part of thefirst reaction zone through line 27. The first reaction zone employed issimilar to the reaction vessel previously described and is equipped withprovision for cooling the reaction in order to maintain the temperaturewithin the desired range for reaction. In addition, the first reactionzone is provided with battles disposed there within so that bettercontact between the fluorine gas and iodine pentafluoride is effected.

Under the technique of operation, the iodine pentafluoride flows downthe first reaction zone 25 countercurrent and in contact with theupflowing fluorine gas causing a reaction between the fluorine gas andthe iodine contained in the iodine pentafluoride. Temperatures up to theactual boiling point of iodine pentafluoride (ca. at about 98 C. atlatm, pressure) may be maintained in the reaction zone 25 withoutseriously eflecting the process efliciency. At higher temperatures, theamount of iodine concentration level in the iodine pentafluorideincreases due to increased solubility and may reach a level of about 5%iodine by weight dissolved in the iodine pentafluoride solution. Thepressure within the first reaction zone 25 is substantially atmosphericpressure authough higher or lower pressures may be employed if desired.The iodine pentafluoride which is produced in the reaction of fluorineand iodine is discharged from first reaction zone 25 through line 28 andthereafter enters a first holding zone 26. First holding zone 26 isequipped with provision for supplying a source of iodine to the iodinepentafluoride. For this purpose, there is provided a chamber or bafliesection 29 which contains iodine crystals. The chamber or baflle sectionmay take the form of a screen constructed of an inert material intowhich are added iodine crystals. By passing the iodine pentafluoridefrom first reaction vessel 25 through the baffle section 29 in contactwith the iodine crystals, the iodine content of the iodine pentafluoridesolution is maintained at the level of saturation depending upon theoperating temperature. Additional cooling is provided in first holdingzone 26 to maintain the desired temperature level.

In addition, the iodine pentafluoride contained in first holding zone 26is maintained at a fixed level by means of an overflow through which theiodine pentafluoride is continuously being discharged during operationof the process. A portion of the iodine pentafluoride solution containedin first holding zone 26 is recirculated to the first reaction zone 25through line 24 by means of a. pump 30 which is disposed within firstholding zone 26 while another portion of the iodine pentafluoride ispassed through line 31 and into a second stage. The second stagecomprises a second reaction zone 33 and a second holding zone 32 ofsimilar constitution and design as in the first stage. The iodinepentafluoride contained in second holding zone 32 is discharged throughline 34 by means of pump 36 and enters the upper portion of secondreaction zone 33 where the iodine pentafluoride passes in countercurrentcontact with fluorine gas which enters the lower part of the reactionzone through line 39. As illustrated in FIGURE 2 of the drawings, thefluorine gas which enters second reaction zone 33 is the unreactedfluorine gas which is discharged from the first reactor 25 although ifdesired, fluorine gas from an external source may be employed. Secondreaction zone 33 is similar to the reaction vessel previously describedand is also equipped with provision for cooling the reaction in order tomaintain the temperature within the desired range for reaction, Anyremaining unreacted fluorine gas in the second reaction zone passesthrough line 37 together with minor amounts of impurities where it isrecovered and if desired recycled back to the first reaction zone 25.Iodine pentafluoride produced in second reaction zone 33 is dischargedthrough line 35 and directed back to the second holding zone 32. Theproduct iodine pentafluoride is discharged from the second stage throughline 38 where, if desired, further purification may be effected, suchas, for example, by passing the iodine pentafluoride to a suitabledistillation apparatus, not shown, to remove possible hydrogen fluoride,iodine, iodine heptafluoride, or fluorine contamination.

Either the entire amount, or a portion of the iodine pentafluorideleaving first reaction zone 25 through line 28 and containing smallamounts of iodine may be directed to the second holding zone 32 throughline 40. Control of feed may 'be eflected by use of valves 41 and 42.This would be advantageous where it is desired to employ an iodinepentafluoride solution in second holding zone 32, which solutioncontains less amounts of iodine dissolved in iodine pentafluoride thanthe iodine pentafluoride solution from the first holding zone 26.

The following examples illustrate the invention.

Example 1 In an operation as illustrated in FIGURE 1, iodinepentafluoride containing about 6.5% iodine by weight was introduced intoa reactor packed with raschig rings at a rate of 30.5 gallons per hourin countercurrent contact with fluorine gas fed to the reactor at a rateof three pounds per hour. The reactor equipment was sized to give acontact time between the reactants of about 18 seconds and thetemperature in the reaction zone was maintained at about 20 to 60 by theiodine pentafluoride solvent and by water cooling. The iodinepentafluoride was continually discharged from the reactor into a producttank where about seven pounds per hour of product iodine pentafluoridewas collected :by overflow.

A portion of the iodine pentafluoride in the product tank was pumpedthrough a leach vessel containing solid iodine crystals suspended in awire basket. The liquid iodine pentafluoride dissolved iodine up to aconcentration of about 1% by weight and was admixed with a portion ofiodine pentafluoride which by-passed the leach vessel to yield aconcentration of iodine in iodine pentafluoride of about 0.5% by weight.The diluted stream was thereafter passed into the top of the reactionvessel in countercurrent contact with fluorine gas. According to theabove procedure, the yields on both fluorine and iodine feeds were about99%.

"Z Example 2 In an operation as illustrated in FiGURE 2, iodinepentafluoride containing about 0.5% iodine by weight was introduced intoa first reaction zone at a rate of 600 gallons per hour incountercurrent contact with fluorine gas fed into the first at a rate of25 pounds per hour. The reactor reaction zone was sized to give acontact time between the reactants of about 5 seconds and thetemperature in the first reaction zone was maintained at about 20 to 60C. by the iodine pentafluoride solvent and by water cooling.

Although certain preferred embodiments of the invention have beendisclosed for purpose or" illustration, it will be evident that variouschanges and modifications may be made therein without departing from thescope and spirit of the invention.

I claim:

1. A process for producing iodine pentafluoride from elemental fluorineand iodine which comprises introducing elemental fluorine in contactwith iodine dissolved in an inert solvent to effect reaction between theelemental fluorine and iodine to produce iodine pentafluoride.

2. A process for producing iodine pentafluoride from elemental fluorineand iodine which comprises introducing elemental fluorine in contactWith a solution of about .1 to 5.0% by weight iodine in iodinepentafluoride at a temperature within the range of to 98 C. to effectreaction between the elemental fluorine and iodine to produce iodinepentafluoride.

3. The process of claim 2 in which the mole ratio of fluorine to iodineis 5.0:1 to 55:1.

4. A process for producing iodine pentafluoride from elemental fluorineand iodine which comprises introducing elemental fluorine incountercurrent contact with a solution of about 0.4 to 1.0% by weightiodine in iodine pentafluoride at a temperature within the range of to60 C. and a mole ratio of fluorine to iodine of 5.0:1 to 5.521 to effectreaction between the elemental fluorine and iodine to produce iodinepentafluoride.

5. A process for producing iodine pentafluoride from elemental fluorineand iodine which comprises continuously passing elemental fluorine incontact with a body of iodine pentafluoride containing dissolved iodinein an amount of about 0.4 to 1.0% by weight in a reaction zonemaintained at a temperature of 20 to 60 C. to effect reaction of theelemental fluorine and iodine to produce iodine pentafluoride,continuously discharging the iodine pentafluoride from the reactionzone, withdrawing a portion of the discharged iodine pentafluoridewithdrawing another portion of the iodine pentafluoride, dissolvingiodine in said second portion and returning said second portion ofiodine pentafluoride containing dissolved iodine to the reaction zone incontact with additional fluorine.

6. A process for producing iodine pentafluoride from elemental fluorineand iodine which comprises continuously passing elemental fluorine incontact with iodine pentafluoride containing dissolved iodine in anamount of about .1 to 5% by Weight in a first reaction zone maintainedat a temperature of 10 to 98 C. to effect reaction of the elementalfluorine and iodine to produce iodine pentafluoride, continuouslydischarging unreacted fluorine gas, continuously discharging the iodinepentafluoride from the first reaction zone and introducing said iodinepentafluoride solution into a first holding zone, dissolving iodine insaid iodine pentafluoride in the first holding zone, withdrawing aportion of iodine pentafluoride from the first holding zone andreturning said portion containing dissolved iodine to the first reactionzone in contact with additional fluorine, withdrawing another portion ofiodine pentafluoride and introducing said portion into a second holdingzone, continuously introducing iodine pentafluoride from the secondholding zone into a second reaction zone in contact with said unreactedfluorine gas from the first reaction zone to effect reaction of fluorineand iodine to produce iodine pentafluoride discharging iodinepentafluoride from the second reaction zone, directing a portion of saiddischarged iodine pentafluoride from said second reaction zone to saidsecond holding zone, and withdrawing and recovering a portion of iodinepentafluoride as a product.

7. A process according to claim 6 wherein the temperatures maintained inthe reaction zones are within the range of 20 to C.

8. A two stage process for producing iodine pentafluoride from elementalfluorine and iodine which comprises contacting in a first stage, iodinepentafluoride with iodine to dissolve the iodine to form a solution ofiodine dissolved in iodine pentafluoride, passing the solution incontact with fluorine in a first reaction zone in said first stage toconvert the iodine dissolved in the iodine pentafluoride to iodinepentafluoride, returning a portion of the iodine pentafluoride forfurther contact with iodine to dissolve iodine in iodine pentafluoride,directing another portion to a second stage wherein the iodinepentafluoride is contacted with fluorine to effect substantiallycomplete removal of iodine to produce iodine pentafluoride, discharginga portion of the iodine pentafluoride from the second stage as aproduct, returning the other portion together with the portion from thefirst stage for further contact with fluorine to produce iodinepentafluoride.

9. A two stage process for producing iodine pentafluoride from elementalfluorine and iodine which comprises contacting in a first stage, iodinepentafluoride with iodine to dissolve the iodine to form a solution ofiodine dissolved in iodine pentafluoride, passing the solution incontact with fluorine in a first reaction zone in said first stage toconvert the iodine dissolved in the iodine pentafluoride to iodinepentafluoride, returning the iodine pentafluoride for further contactwith iodine to dissolve iodine in iodine pentafluoride, circulating aportion of the iodine pentafluoride containing dissolved iodine to thefirst reaction zone as said solution, directing another portion of saidiodine pentafluoride containing dissolved iodine to a second stagewherein the iodine pentafluoride is contacted with fluorine to effectsubstantially complete removal of iodine to produce iodinepentafluoride, discharging a portion of the iodine pentafluoride fromthe second stage as a product, returning the other portion together withthe portion from the first stage for further contact with fluorine toproduce iodine pentafluoride.

References Cited FOREIGN PATENTS 5/1961 U.S.S.R. 4/1961 Germany.

OTHER REFERENCES OSCAR R. VERTIZ, Primary Examiner.

G. T. OZAKI, Assistant Examiner.

